Did you check all the vacuum lines? Mine would blink on the dash and try to go into 4hi, but no vacuum. I found 3-4 bad spots on the vacuum lines. Once replaced, they worked.

 

Checked the vacuum line all were good..

My dash switch won't blink at all..

 

The 4x4 dash switch should only blink when switching between modes; 2HI, 4HI, 4LO and then whatever mode was selected the small lite in the button should stay on.

I assume that when you tried the known good TCCM and dash switch that there was no difference in operation, correct?

To me, then it has to be the wiring between the two....so back to the connectors unless there is a possibility that something has gotten into the vehicle and chewed-up the wiring under the dash...????

 

I highly doubt anything got into the dash and chewed up the wires..

And correct there was no difference when known good parts were swapped in..

And I got absolutely no lights on the dash switch besides the back lighting but the 2 hi light is not on like it usual was while in 2 hi and I can't switch to 4 hi 4 lo or auto 4wd .. i get no response or noises when I push aany of the buttons for 4wd

 

At this point I suggest getting a detailed wiring diagram and check continunity between the 4x4 switch and the TCCM connectors. There has got to be a break between the two as they are not "talking" to one another.

Check all the fuses as I do not know which fuse/circuit power the TCCM and 4x4 switch.

Wow....good luck.

 

Bought my truck to the mechanic. . He tested all the wires and everything is getting power ground and correct ohms..

So we suspected either tccm or encode4 motor.. so we swapped in a different tccm and that actually worked.. so I bolted the different tccm in place put the kick panel back on and went to back out of the garage and when I started the truck the service 4wd light came back on.. so we thought loose wire In comment or going into tccm but couldn't find any at fault wires..
My mechanic thinks the tccm needs to be re programmed. . I thought they were plug and play?? Is this true? Or does it need to be re programmed

 

They are plug and play.

Did your mechanic read the codes stored in the TCCM? It would be a good place to start as it will give direction to the actual cause of the problem.

 

Yes he did.. If I remember correctly it was c0308. . I'm double checking with my mechanic if that's the code..

 

C0308 - Motor A/B Circuit Low

From the OBD2 DTC section.

 

Is it the lights not working? I had that issue and I replaced the switch and now it's working. You can tell if it's engaging in 4wd by the way it drives.